NeoCare, UMR INRA/ENVT 1225 IHAP, Reproduction, Université de Toulouse, 23 Chemin des Capelles, 31076 Toulouse, Cedex 03, France.
Royal Canin, 650 Avenue de la Petite Camargue, 30470, Aimargues, France.
Prev Vet Med. 2019 Nov 1;171:104746. doi: 10.1016/j.prevetmed.2019.104746. Epub 2019 Aug 13.
In numerous species, low birth weight is a risk factor for neonatal mortality. In the canine species, definition of a low birth weight is complex due to the huge interbreed variability in size. To identify puppies at higher risk of neonatal death, data from 6,694 puppies were analysed. The data were collected from 75 French breeding kennels, examining 27 breeds and totaling 1,202 litters of puppies. Generalised linear mixed models allowed to identify birth weight, birth weight heterogeneity within the litter, and size of the breeding kennel as significant risk factors for neonatal mortality. Receiver Operating Characteristics (ROC) and classification and regression tree (CART) analyses were combined to define breed specific thresholds for birth weight allowing the identification of puppies at higher risk of neonatal mortality. Due to differences in birth weights between breeds, including when belonging to the same breed size, analyses were conducted at the breed level. First, ROC analysis thresholds were successfully established for 12 breeds (area under the ROC ≥ 0.70; sensitivity ≥ 75%; specificity: 45-68%) and they ranged from 162 g in the Maltese to 480 g in the Bernese Mountain dog. Secondly, CART analysis thresholds from 22 breeds ranged from 105 g in the Maltese and 436 g in the Boxer. Puppies were grouped into three categories according to birth weight: low, moderate and high risk of neonatal mortality (higher than the ROC threshold, between ROC and CART thresholds, and lower than the CART threshold respectively). In the current study, 44% of the puppies were classified as at moderate risk and 5.3% for a high risk of neonatal mortality. Thresholds defined by CART analysis (and not ROC analysis) were used to define low birth weight puppies and were sometimes quite different between breeds with similar birth weight distributions suggesting a variable relationship between birth weight reduction and neonatal death. These results allow the identification of puppies at an increased risk of neonatal death, thus requiring specific nursing to improve their chances of survival. With these high risk puppies identified, both animal welfare and kennel productivity is predicted to improve.
在许多物种中，低出生体重是新生儿死亡的一个风险因素。在犬种中，由于体型的巨大种间变异性，低出生体重的定义很复杂。为了确定新生儿死亡风险较高的小狗，分析了 6694 只小狗的数据。这些数据来自 75 个法国繁殖犬舍，检查了 27 个品种，共有 1202 窝小狗。广义线性混合模型允许确定出生体重、窝内出生体重异质性以及繁殖犬舍的大小是新生儿死亡的重要危险因素。接受者操作特征（ROC）和分类回归树（CART）分析相结合，确定了特定于品种的出生体重阈值，以确定新生儿死亡风险较高的小狗。由于不同品种的出生体重不同，包括属于同一品种大小的情况，因此在品种水平上进行了分析。首先，成功地为 12 个品种建立了 ROC 分析阈值（ROC 下面积≥0.70；敏感性≥75%；特异性：45-68%），范围从 162 克的马尔济斯犬到 480 克的伯恩山犬。其次，22 个品种的 CART 分析阈值范围从 105 克的马尔济斯犬到 436 克的拳击犬。根据出生体重将小狗分为三组：新生儿死亡的低、中、高风险（高于 ROC 阈值、ROC 和 CART 阈值之间以及低于 CART 阈值）。在本研究中，44%的小狗被归类为中度风险，5.3%的小狗为新生儿死亡的高风险。CART 分析（而非 ROC 分析）定义的阈值用于定义低出生体重的小狗，并且在具有相似出生体重分布的品种之间有时非常不同，这表明出生体重降低与新生儿死亡之间的关系存在差异。这些结果允许确定新生儿死亡风险增加的小狗，因此需要特殊护理以提高它们的生存机会。有了这些高风险的小狗被识别出来，动物福利和犬舍的生产力预计都会得到提高。
